Molecular characteristics and antibiotic resistance of Vibrio parahaemolyticus using whole genome sequencing

ObjectiveTo understand the genomic characteristics and drug resistance of Vibrio parahaemolyticus （VP） isolated in Dalian City， and provide necessary data support for VP molecular tracing， virulence gene analysis， and drug resistance mechanism research.MethodsThis study conducted whole genome sequencing and drug sensitivity tests on 96 strains of VP isolated in Dalian City in 2023. The whole genome sequencing datas were assembled using the Beijing Micro Future Pathogenic Microbial Information Analysis System. The assembled genome sequences were subjected to MLST， cgMLST， and cgSNP analysis. Virulence genes and drug resistance genes were also analyzed， and a comparative analysis of drug resistance genes and phenotypes was conducted.ResultsNinty-six strains of VP were divided into 9 ST types， with ST3 being the most prevalent.The 96 strains of VP were classified into 96 cgMLST and cgSNP types， exhibiting rich genetic diversity. Ninty-six strains of VP carried a large number of virulence genes， with a total of 16 virulence genes showing differences （χ2=72.004， P<0.001）， and each strain carried at least 11 virulence genes. A total of 19 drug resistance genes showing differences （χ2=1539.1， P<0.001）， with the highest carriage rates of CARB， CRP， and tet（35） genes， all at 98.96%； the carriage rates of other drug resistance genes were 1.04%. The resistance rates to ampicillin and colistin were high， at 57.29% and 46.88% respectively， and the sensitivity to streptomycin decreased， with an intermediate rate of 53.13%. Only 4 strains were multidrug-resistant.ConclusionsThe 96 strains of VP isolated in Dalian City in 2023 exhibit genetic diversity， and carry virulence genes and drug resistance genes， showing resistance to ampicillin and colistin. This study also demonstrated that whole genome sequencing technology can provide necessary data support for molecular tracing， virulence gene analysis and drug resistance mechanism research of pathogenic bacteria.